NEW ORLEANS (AP) -- As authorities investigate the cause of the 34-minute Super Bowl blackout, documents show Superdome officials were worried in the fall about losing power at the big game.

The authorities warned in an Oct. 15 memo that tests on the dome's electrical feeders showed decay and "a chance of failure."

Subsequently, members of the state commission responsible for the dome authorized spending nearly $1 million on improvements, including more than $600,000 to upgrade the electrical feeder cable system. That work was done in December.

The blackout embarrassed New Orleans just when it was hoping to show the world how far it has come since Hurricane Katrina in 2005. But many fans were forgiving, and officials expressed confidence that the episode wouldn't prevent New Orleans from hosting future Super Bowls.